Soft-mode behavior and incipient ferroelectricity in Na1/2Bi1/2Cu3Ti4O12.
Result description
Na1/2Bi1/2Cu3Ti4O12.(NBCTO) ceramics exhibit high intrinsic relative permittivity of 145 at 300 K that rises on cooling and levels off below 50 K with a value of 260 at 10 K without any signature of a structural transition. Such behavior is a typical feature of incipient ferroelectrics such as the perovskite CaTiO3. Infrared and terahertz spectroscopy on NBCTO ceramics are presented and reveal a room-temperature soft polar optic mode at 34 cm-1 that softens on cooling and is responsible for the temperature dependence of the relative permittivity. The temperature dependence of the soft-mode frequency obeys the Barrett formula with the onset of quantum fluctuations T1 occurring near 85 K and a hypothetical Curie temperature T0 of 155 K. A fitted vibrational zero-point energy (kBT1)/2 is in good agreement with the measured soft-mode frequency.
Keywords
infrared and terahertz spectroscopysoft modeincipient ferroelectrics
The result's identifiers
Result code in IS VaVaI
Result on the web
—
DOI - Digital Object Identifier
—
Alternative languages
Result language
angličtina
Original language name
Soft-mode behavior and incipient ferroelectricity in Na1/2Bi1/2Cu3Ti4O12.
Original language description
Na1/2Bi1/2Cu3Ti4O12.(NBCTO) ceramics exhibit high intrinsic relative permittivity of 145 at 300 K that rises on cooling and levels off below 50 K with a value of 260 at 10 K without any signature of a structural transition. Such behavior is a typical feature of incipient ferroelectrics such as the perovskite CaTiO3. Infrared and terahertz spectroscopy on NBCTO ceramics are presented and reveal a room-temperature soft polar optic mode at 34 cm-1 that softens on cooling and is responsible for the temperature dependence of the relative permittivity. The temperature dependence of the soft-mode frequency obeys the Barrett formula with the onset of quantum fluctuations T1 occurring near 85 K and a hypothetical Curie temperature T0 of 155 K. A fitted vibrational zero-point energy (kBT1)/2 is in good agreement with the measured soft-mode frequency.
Czech name
—
Czech description
—
Classification
Type
Jx - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)
CEP classification
BM - Solid-state physics and magnetism
OECD FORD branch
—
Result continuities
Project
Continuities
Z - Vyzkumny zamer (s odkazem do CEZ)
Others
Publication year
2010
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Physical Review. B
ISSN
1098-0121
e-ISSN
—
Volume of the periodical
81
Issue of the periodical within the volume
22
Country of publishing house
US - UNITED STATES
Number of pages
6
Pages from-to
—
UT code for WoS article
000279090100001
EID of the result in the Scopus database
—
Result type
Jx - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)
CEP
BM - Solid-state physics and magnetism
Year of implementation
2010